Tanks used for storing or transporting flammable fluids such as gasoline, diesel fuel and other petroleum products are often equipped with protection devices. When the fluids are being transferred from the storage tanks to recipient tanks, these devices detect when the recipient tanks are full and automatically disable the transfer process. Tanks can be mounted on tanker trucks or located underground at service stations. Tanker trucks are typically filled with the fluids using pumping equipment at the loading racks of marketing terminals, and underground storage tanks are typically gravity-filled from the trucks.
Asphalts also are transferred in a similar fashion. Asphalts are well known and widely used in a variety of products. While asphalts are primarily composed of high molecular weight hydrocarbons, they invariably contain minor amounts of low molecular weight hydrocarbons exhibiting substantial volatility. As such, the manufacture, storage and transportation of asphalt materials present opportunities for escape of the volatile, organic components (VOCs) into the atmosphere.
Odor control and fume recovery would be highly desirable. A wide variety of systems exists for treating asphalt vapors. These systems collect, adsorb, absorb, oxidize, react, suppress or perfume the asphalt vapors. Additives such as citrus terpenes and cherry odor additives merely mask the problem.
Recent developments in odor control and drop tube assemblies are disclosed in U.S. Pat. Nos. 6,935,387 and 7,225,840, the disclosures of which are herein incorporated by reference.
The apparatus of this invention represents a further improvement in rack opacity filtering systems.